Elign: Equivariant Diffusion Model Alignment from Foundational Machine Learning Force Fields

Fuente: arXiv
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Autores principales: Li, Yunyang, Huang, Lin, Xia, Luojia, Zhang, Wenhe, Gerstein, Mark
Formato: Preprint
Publicado: 2026
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author Li, Yunyang
Huang, Lin
Xia, Luojia
Zhang, Wenhe
Gerstein, Mark
author_facet Li, Yunyang
Huang, Lin
Xia, Luojia
Zhang, Wenhe
Gerstein, Mark
contents Generative models for 3D molecular conformations must respect Euclidean symmetries and concentrate probability mass on thermodynamically favorable, mechanically stable structures. However, E(3)-equivariant diffusion models often reproduce biases from semi-empirical training data rather than capturing the equilibrium distribution of a high-fidelity Hamiltonian. While physics-based guidance can correct this, it faces two computational bottlenecks: expensive quantum-chemical evaluations (e.g., DFT) and the need to repeat such queries at every sampling step. We present Elign, a post-training framework that amortizes both costs. First, we replace expensive DFT evaluations with a faster, pretrained foundational machine-learning force field (MLFF) to provide physical signals. Second, we eliminate repeated run-time queries by shifting physical steering to the training phase. To achieve the second amortization, we formulate reverse diffusion as a reinforcement learning problem and introduce Force--Energy Disentangled Group Relative Policy Optimization (FED-GRPO) to fine-tune the denoising policy. FED-GRPO includes a potential-based energy reward and a force-based stability reward, which are optimized and group-normalized independently. Experiments show that Elign generates conformations with lower gold-standard DFT energies and forces, while improving stability. Crucially, inference remains as fast as unguided sampling, since no energy evaluations are required during generation.
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id arxiv_https___arxiv_org_abs_2601_21985
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Elign: Equivariant Diffusion Model Alignment from Foundational Machine Learning Force Fields
Li, Yunyang
Huang, Lin
Xia, Luojia
Zhang, Wenhe
Gerstein, Mark
Machine Learning
Generative models for 3D molecular conformations must respect Euclidean symmetries and concentrate probability mass on thermodynamically favorable, mechanically stable structures. However, E(3)-equivariant diffusion models often reproduce biases from semi-empirical training data rather than capturing the equilibrium distribution of a high-fidelity Hamiltonian. While physics-based guidance can correct this, it faces two computational bottlenecks: expensive quantum-chemical evaluations (e.g., DFT) and the need to repeat such queries at every sampling step. We present Elign, a post-training framework that amortizes both costs. First, we replace expensive DFT evaluations with a faster, pretrained foundational machine-learning force field (MLFF) to provide physical signals. Second, we eliminate repeated run-time queries by shifting physical steering to the training phase. To achieve the second amortization, we formulate reverse diffusion as a reinforcement learning problem and introduce Force--Energy Disentangled Group Relative Policy Optimization (FED-GRPO) to fine-tune the denoising policy. FED-GRPO includes a potential-based energy reward and a force-based stability reward, which are optimized and group-normalized independently. Experiments show that Elign generates conformations with lower gold-standard DFT energies and forces, while improving stability. Crucially, inference remains as fast as unguided sampling, since no energy evaluations are required during generation.
title Elign: Equivariant Diffusion Model Alignment from Foundational Machine Learning Force Fields
topic Machine Learning
url https://arxiv.org/abs/2601.21985